Afsin-Elbistan Lignite Research Articles

Influence of the addition of various ionic liquids on coal extraction with NMP

In this work, two Turkish coals were extracted with N-methyl-2-pyrrolidone (NMP) and NMP containing a small amount of ionic liquids (ILs) under reflux conditions at atmospheric pressure. The effects of coal type, ionic liquid type, ionic liquid-to-coal ratio, and ultrasonic interactions on extraction yield were investigated. The ILs used were: 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), 1-buty-4- methylpyridinium chloride ([Bmp]Cl), 1-ethyl-3-methylimidazolium chloride ([Emim]Cl), and 1-butyl-2,3-dimethylimidazolium chloride ([Bdmim]Cl). It was found that the extraction yield of coals using NMP/ILs varied with coal type, IL type and amount of IL. ILs were effective on the extraction of Afsin-Elbistan (AE) lignite, but not on the extraction of Üzülmez (UZ) coal. A significant increase in extraction yield for AE lignite was observed when a small amount of IL was added into NMP. It was determined that [Bmim]Cl was the most efficient IL used for the extraction of lignite compared to the others ILs used, and the extraction efficiency was found to increase by increasing the amount of ionic liquid added into NMP.

Development of a GIS-based information system for mining activities: Afsin-Elbistan lignite surface mine case study

In this study, it was aimed to monitor mining activities and product movements by establishing a mine information system and to give the optimum decision by conducting the necessary inquiries and analyses. For this purpose, at first the map materials used in the mining activities in Afsin-Elbistan lignite basin were converted to digital maps by means of GIS techniques, and after that the lignite deposit was modelled in 3D, by utilising drill holes data and geostatistical methods. With the integration of the table and graphical data obtained in this way in GIS environment, performance of location-dependent analysis, such as the determination of reserve-quality distributions, was made possible. Within this scope, it was demonstrated that the reserve quantities and statistical information of all attributes included in the databases selected from the screen or of any other databases generated through inquiries are accessible, and also thematic maps can be generated.

Burnout characteristics during co-combustion of binary lignite blends

Binary lignite blends were prepared using two high mineral matter Turkish lignites from Soma and Afsin-Elbistan regions and their burnouts were investigated up to 900°C by thermogravimetric analysis and differential thermal analysis methods. Blending ratios were in the range of 5–25 wt-% in which Afsin-Elbistan lignite was the major component. Mass losses during co-combustion were considered to interpret the thermal reactivity and the burnout characteristics of the blends according to synergistic approach. It was concluded that co-combustion of the lignite blends led to significant increases in the burnout yields almost at any temperature. Besides, increasing blending ratios changed the behaviour of blends from additive behaviour to the synergistic interaction. Especially, blending ratio of 15 wt-% showed important deviations from the expected values in terms of burnouts, maximum burning rate and differential thermal analysis peak temperature.

Determination of Vegetation Change Using Thematic Mapper Imagery in Afşin-Elbistan Lignite Basin; SE Turkey

In this study Landsat Thematic Mapper (TM) and Landsat Enhanced Thematic Mapper plus (ETM+) data for the years 1989-2000-2010 was used to detect vegetational change in Afsin Elbistan lignite basin. Study based on application of Normalized Difference Vegetation Index (NDVI). The change of vegetation cover is determined by comparing different date NDVI images using differencing method. Differencing NDVI images helped to quickly identify areas where vegetation is increased or decreased. The results suggest that NDVI have revealed significant changes in green vegetation in the study area. Remote sensing techniques and multi temporal satellite data reliably used to monitoring changes of vegetation cover in open pit mine areas.

Combustion Characteristics of the Original and Demineralized Afsin-Elbistan Lignite and Its Char

Simultaneous thermal analysis and mass spectrometry were used to determine the combustion characteristics of the original and demineralized Afsin-Elbistan lignite and its char. The major gaseous products evolved were characterized. An integral method was applied for kinetic calculations. The demineralized lignite shows the highest overall reactivity for combustion. A pronounced decrease of the final combustion temperature and activation energy of combustion is observed for the demineralized case. The differences observed in SO2 emissions of the original and demineralized lignite and char are primarily due to the adsorption and/or chemisorption of SO2 by the calcium oxides of the mineral matrix.

Two and three dimensional analysis of a slope failure in a lignite mine

With about 9.3 billion tons of reserve, lignite is a major source for energy production in Turkey. The Afşin–Elbistan lignite basin, containing 47% of the overall lignite reserve in Turkey, lies in the Afşin and Elbistan districts as a part of Kahramanmaraş. The new Çöllolar opencast mine is in the Afsin–Elbistan lignite basin, and this mine will be the second mining activity in the basin after the active Kışlaköy opencast mine. The new mine will meet the coal consumption of the Elbistan B power plant. Input parameters for slope stability analysis are essential, and so they must be determined accurately and precisely. Field investigations, laboratory testing and back analyses are vital instruments for the input parameters. This study presents the results of slope stability analysis via finite difference code and a limit equilibrium software for the soil slopes of the Elbistan–Çöllolar lignite mine. The basic input parameters, cohesion and friction angle, were determined in the soil mechanics laboratory. By back analyses of a large scale slope failure, mobilized friction angles for a critical weak clay layer under the lignite seam were determined accurately by using the 2D limit equilibrium method and 3D finite difference models. Results of the friction angles were compared in order to check the effectiveness of commonly used 2D approaches in handling the slope problems. Differences in the results of the mobilized friction angles for the weak clay layer were more than 30%. The 3D models indicated that the mobilized friction angle during the major slope failure was substantially lower than the friction angle generated by the 2D limit equilibrium method.

Measuring Dependence between Calorific Values of Lignite and Spatial Positions by Rank Correlation Method: A Case Study

This article presents an investigation for evaluating the relationship between calorific value of lignite and its spatial position using non parametric statistics. Measuring dependence between calorific values and spatial positions is important for production planning and making decisions. For this purpose, a three dimensional data set (easting-x, northing-y, and elevation-z) obtained from Afsin-Elbistan lignite deposit is employed. Rank correlation measurements have been carried out between spatial dimensions and calorific values. In addition, the significances of rank correlation coefficients have been appraised using hypothesis tests. As a result of the study, a strong rank correlation between y and calorific values and a weak rank correlation between z and calorific values are observed, respectively. On the other hand, very low-rank correlation between coordinate x and calorific values is measured for the deposit.

Geotechnical characterization of lignite-bearing horizons in the Afsin–Elbistan lignite basin, SE Turkey

The Afsin–Elbistan lignite deposit, with its 3.4 billion metric tons of reserves, is the biggest lignite basin and one of the most important resources for electrical energy production in Turkey. Kislakoy mining field was selected as the first opencast mine to feed four power station blocks of 300 MW each. Slope instability has been a continuing problem in the Kislakoy opencast mine. Particularly complex failures along a noncircular failure surface appearing at the final slope stage and covering large areas in the mine increase the importance of slope stability. This study outlines the geotechnical characteristics of the lignite-bearing horizons and describes the causes and mechanisms of slope instabilities, which threaten the safety of the mine. Quantitative X-ray diffraction (XRD) analyses were carried out using an interactive data processing system (SIROQUANT™) based on Rietveld interpretation methods. Parametric slope stability analysis and backanalysis were carried out for the failure that occurred at the northwestern final slope stage of the mine. The Spencer–Wright limiting state equilibrium method was used in order to determine with confidence the most representative values of regional shear strength parameters, to explain the failure mechanism, and to assess the conditions at the time of failure. In the analysis, phreatic and piezometric surfaces were considered. Site observations and numerous backanalyses of the slope failure reveal that a compound slide occurred where gyttja (contact zone) layers rest directly on the lignite. Gyttja (contact zone) contains the weakest material within the system. The analysis showed that the main cause of the northwestern slope instability was the presence of the groundwater flow within a Quaternary aquifer (through buried valleys), reducing the effective shear strength of the slope materials. It is also noted from backanalysis that the gyttja (contact zone) layer presents a shear strength at, or approaching, the residual value at the time of failure.

Environmentally Sound Coal-Derived Binder for Coal Briquetting

Conventional coal binders such as coal tar pitch and petroleum refinery residue provide agglomerates of satisfactory quality. However, their use has been banned for a quarter century due to their hazardous effect on human health and their contribution to air pollution. On the other hand, environmentally sound binders such as molasses, dextrin, etc. provide poor water-resistant agglomerates. In this research, coal-derived humic acid was used as coal binder. It was extracted from Afsin-Elbistan lignite by nitric acid oxidation and ammoniation processes. During briquetting, the effect of heat treatment, amount of binder added, particle size, pressure, and moisture content of the briquetting charge on the quality of the briquette have been investigated. The briquette produced at 165°C for 1 h heat treatment by adding 5% humic acid and 10.50% moisture showed that the radial compressive strength was 80 kg/briquette and abrasion resistance was 87.03%, with no water disintegration.

Preliminary Analyses of Radionuclides in Afşin-Elbistan Lignite Samples

This preliminary study describes the concentration of radionuclides 238U, 232Th, 40K, and 226Ra in Afsin-Elbistan lignite samples which are primarily used for power generation in the Afsin-Elbistan Coal-Fired Power Plant. The results show that the concentration of 238U is higher in the Afsin-Elbistan lignite compared to various world coals whereas the opposite is observed with 232Th and 40K.